US1960814A

US1960814A - Apparatus for shearing

Info

Publication number: US1960814A
Authority: US
Inventors: Iversen Lorenz
Original assignee: Mesta Machine Co
Current assignee: Mesta Machine Co
Priority date: 1933-02-02
Filing date: 1933-02-02
Publication date: 1934-05-29
Anticipated expiration: 1951-05-29

Description

y 29, 1934- L. IVERSEN 1,960,814.

APPARATUS FOR SHEARING I Filed Feb. 2, 1933 3 Sheets-Sheet l fw. l

Ii: '18 1 i .20 I i I l INVENJ'OR y 1934- L. IVERSEN 60,814

APPARATUS FOR SHEARING Filed Feb. 2, 1933 3 Sheets-Sheet 2 k 2 s 5 b Patented May 29, 1934 V UNITED STATES I PATENT OFFICE Machine Company, Homestead,

tion of Pennsylvania Pa., a corpora- Application February 2, 1933, Serial No. 654,818

1'! Claims. (Cl. 16468) My invention relates broadly to the art of metal working and, more particularly, to a control system for rotary shears whereby they may be employed for cutting lengths of material into pieces having a given length.

This is a continuation in part of my co-pending application Serial No. 284,193, filed June 9, 1928, for Method of and apparatus for shearing.

It is well known in the artof shearing material to operate an intermittent reciprocating shear by the engagement of the leading end of the material entering the shear with a flag or other equivalent device. Shears of this type have the advantage that after each shearing cut,

' they always return to their initial position. It is thus possible accurately to determine the length of material cut from the leading end of the. piece by properly positioning the flag. It is obvious that the three factors determining the length of the initial cut, namely, the distance between the flag and the shear, the speed of the material, and the time necessary for the shear to move from its initial to its cutting position, may be adjusted to provide almost any desired result.

It is also known in the shearing art that a rotary shear is capable of operating at much higher speeds than shears of the reciprocating type. The use of rotary shears heretofore, however, despite their higher speed of; operation,

has been strictly limited because it has not been fixed initial position so that a predetermined successive lengths.

front end crop may be made on the first cut of As heretofore employed, rotary shears have been effective to make a front end crop of variable length up to the maximum length for which the shear is operated. Such waste of material, obviously, has made it impractical to employ rotary shears for the purposes herein contemplated.

I have invented a control system for rotary shears such that shears of this type can be employed for cropping the front ends of successive lengths, as well as for continuously cutting said lengths into short sections of predetermined length, as well as into longer sections, for example, cooling bed lengths. My invention causes a rotary shear to return to a predetermined initfal position upon stopping, regardless of whether it has been operated to make a single front end cropping cut or a plurality of successive cuts in shearing" a length into sec-- tions. Since a rotaryshear may be made to return always to the same initial position, by my e'ration.

invention, it is then possible to use shears of this type for making front end cropping cuts as well as intermediate cuts, and thereby to take advantage of the higher speed of operation characterizing rotary shears when compared to the earlier types of reciprocating shears.

In accordance with my invention, I provide a control system for a rotary shearwhich causes the shear operating motor to pass through a predetermined cycle between each cutting op- The movement of the shear blades is arrested at on point in each cycle, regardless of whether the shear is being operated continuously to cut short sections or at longer intervals to shear cooling bed lengths. The operation of the in shear motor is controlled by a drum type controller which is directly connected to the motor shaft. The controller is effective to bring about the desired changes in the motor circuit at the proper times and, after each cutting. operation, to bring the motor and'the shear to rest in a predetermined position. The members of the drum controller are preferably adjustable to provide flexibility in the operating cycle.

For a more complete understanding of the invention, reference is made to the accompanying drawings illustrating a present preferred embodiment'. It is to be understood, however, that many changes in the apparatus and circuits described and illustrated can be made within the scope of my broader claims. In the drawings:

Figure 1 is a diagrammatic plan view showing a rotary shear and a run-out table adapted to receive material, for example, from the last stand of a continuous mill, for delivering it to the rotary shear;

Figure 2 is a sectional view IIII of Figure 1;

Figure 3 is a graphical representation of the operating cycle of the shear and motor:

Figure 4 is a sectional view substantially along the line IV-IV of Figure 1 showing the details of the construction of the drum controller;

lgigure 5 is an end elevation of the controller; an

Figure 6 is a circuit diagram illustrating the electrical connections insuring the desired sequence of operations in each shearing cycle.

Referring now in detail to the drawings and, for the moment, to Figures 1 and 2, the preferred embodiment of my invention comprises a shear 10 of any desired construction. As an example, I have shown a shear having housings 11 with cylinders 12 mounted on shafts 13 journaled in the housings. The cylinders are provided with shear- 110 along the line ing blades 14 which cooperate to effect a severance ofmaterial fed thereto. The cylinders are connected by spur gears 15 in the usual manner so that their speeds bear a predetermined relation to each other.

A run-out table 16 is disposed in position to deliver material to the shear 10. The table is indicated diagrammatically by the conveying rolls 17 thereof since the details of such tables are well known and need no description here. A flag 18 is positioned adjacent the table so as to be operated by material moving therealong, such as the piece indicated at 19. Contacts 20 are bridged by a conducting member actuated by the flag when the latter is engaged by the piece 19.

A motor 21 is provided for driving the shear 10 and is connected thereto through speed reducing gearing 22 and a coupling 23.. The motor 21 is preferably a standard mill type motor and is provided with a brake 24 of the usual type having an electromagnet effective to release the brake when current is supplied to the motor, the brake being set by mechanical means, such as a spring,

a cylindrical housing 26 having an end wall 27, a.

removable cover 28 and an attaching rim 29.by which it may be secured to any convenient support, such as the frame ofthe brake 24. The end wall 27 has a central opening for receiving the reduced end 30 of the shaft of the motor 21 which is indicated at 31. Pinion teeth are formed on the reduced end 30 for meshing with a gear 32 secured to a shaft 33 for driving the latter.

The shaft 33 is journaled in bearing sleeves 34 and 35. The sleeve 34 is positioned in a central opening in the end wall of an adjustable contact cup 36 which is rotatably positioned in a seat 37 machined on the interior of the housing 26. A set screw 38 holds the cup 36 in adjusted position. Contact fingers 39 and 40 extend radiallythrough the side wall of the cup 36 for cooperation with a conducting segment 41 secured to but insulated from the shaft 33. 4

Contact

fingers

42 and 43 for cooperation with a conducting segment 44 also mounted on but insulated from the shaft 33, extend radially through a cylindrical ring 45 similar to the cup 36 except that it has no end wall. The ring 45 and the cup 36 have a machined fit at 46. A set screw 4'7 holds the ring 45 in adjusted position.

The sleeve 35 forming the left-hand bearing for the shaft 33 as viewed in Figure 4 is positioned in a hub 48 formed on a disc 49 which constitutes

tact fingers

51 and 52. insulating bushings 58 extend through the side wall of the housing 26 for receiving control circuit conductors secured to suitable terminals on the contact fingers.

An adjusting handle 59 is secured to the hub 48 by set screws 60 and has a retractible knob 61 at the free end thereof. The knob 61 has a plunger 62 which is normally urged by a spring 63 to enter one of a seriesof holes 64 in the cover 28. A pointer 65 is provided on the handle I 59 for cooperation with any desired indicating scale (not shown).

Movement of the handle 59, of course, shifts the position of the disc 49 and the ring 50, as well as the

fingers

51 and 52 relative to the segment 57. The

rings

36 and 45 are secured in their initially adjusted position by the

set screws

38 and 47. The position of the

fingers

51 and 52 relative to the segment 57, of course, determines the instant during the shearing cycle at which the dynamic braking begins. The setting of the handle 59 thus determines the initial position of the shear blades and, therefore, the length of the initial cut. It is possible to vary the length of the pieces cut by changing the gear ratio be tween the shaft 31 and the shaft 33. Ordinarily, however, the device will be designed to shear a certain fixed length at all times.

' The operation of the'shearing apparatus controlled in accordance with my invention may be 4 best understood by an explanation of Figure 6 in which the various pieces of apparatus are illustrated schematically, together with the control circuits connecting them. As before stated,

Figure 3 illustrates graphically the desired cycle of operations. based on a polar coordinate system except that the zero is not at the origin but at a fixed distance therefrom. The radius 1' indicates zero speed or,

in other words, the stationary position of the shear. The radius R indicates the full speed of the shear. The control system to be described presently is effective for starting the system from rest indicated by the line OX and accelerating through the angle A with the increase in speed indicated in Figure 3. When the shear has reached its full speed at which the shear blades travel at substantially the same speed as the material being fed to the shear, the blades 14 engage the material at some point in the angle C, such as that indicated at C? to effect a shearing cut. Immediately after the shearing cut, I provide for dynamic braking of the shear motor through the angle DB. During this interval, the speed of the shear and motor is decreased as indicated, but when it has reached a predetermined value, it is maintained constant for a time, as shown in the angle CS. During this interval, the motor and shear are driven at .a low, creeping speed. The next and concluding step in the cycle is the application ofthe brake 24 to stop the shear and motor at a given point in the cycle. Succeeding cycles are a repetition of that just described. Since the motor and shear are moving at the same speed, in every cycle, when the electromagnetic brake is released, the extent of drifting movement is always the same so that the point at which the shear and motor actually stop may definitely be predetermined. The point at which the movement of the shear and motor at creeping speed terminates, fixes the initial or stopping position, and the drum switch shown in Figures 4 and 5 permits ready adjustment of this instant, as will now be more fully explained.

In addition to the shear motor anddrum switch, Figure 6 includes other auxiliary control devices which are of standard design, require no specific This graphical representation is description, and will, therefore, be pointed out as the description of operation proceeds.

in its upper position, to the supply at 71. contactor 72 closes and completes a circuit at its Current is supplied to the armature 21a and series field 21 of the shear motor 21 from a supply source indicated at 70, 71, under thecontrol of a main contactor 72 having a closing coil 720. A push button switch 73 is provided for effecting operation of the shear under manual control. A switch 74 is provided for efiecting continuous operation.

If it is desired to effect a single front'end cropping cut of a piece of material, such as 19, the push button switch 73 is held closed as the piece is delivered by the run-out table 16 to the shear 10.

The shear is stationary undernormal conditions.-

If the switch 73 is held closed, a circuit will be completed for the coil 720 of the contactor 72 by the flag 18 at a predetermined time in advance of the arrival of the leading end of the piece at the shear, depending upon the speed of the material and the distance between the flag and the shear. This circuit extends from the supply source at through the switch 73, the coil 72c, and the contacts 20 bridged by the flag switch The main contact 72m for the motor 21. This circuit extends from the supply source at 70 through the contact 72171., the contactor 72, the series field 21 f and the armature 21a of the shear motor 21, a starting resistor 75, and a release coil of the magnet 24 indicated at 24c, to the supply at 71. The shunt field 21s is simultaneously energized.

The drum switch 25 is shown developed in Figure 6, in accordance with the usualconvention. In the initial position of the shear, the segment 44 of the drum switch bridges its

contact fingers

42 and 43. The operation of the contactor 72 thus completes a sealing circuit for the coil 72c 01" the contactor through its auxiliary contact 72a, the circuit extending from the supply at 70, the main contact 72m, the contactor 72, its auxiliary contact 72a, contact finger 42, segment 44, contact 43 of the drumswitch, the coil 720 of the contactor, and the contacts 20 bridged by the flag 18 to the supply at 71. When the contactor 72 has been closed and locked in, as described, the push button switch 73 is released or, in other words, the push button may be released almost instantaneously after the engagement of the piece 19 with the fiag 18.

The motor circuit being completed as above described, the motor 21 accelerates to bring the shear blades up to the speed of the material on the table 16. As the motor speeds up, it advances the drum switch 25 and after a predetermined interval, the segment 41 engages the contact fingers 39 and 40 to complete an obvious energizing circuit for the operating coil 760 of the contactor '76. The energization of the coil closes the contact and shunts the starting resistor 75, placing the shear. motor directly across the supplylsource 70, 71. The motor 21 thus quickly reaches its shearing speed.

By the time the motor has reached full speed, the shear blades have moved from their initial position to the cutting position, indicated at C? in Figure 3. Shortly after the completion of the cut, the segment 41 leaves its contact fingers 39 and 40. The contactor coil 760 is thus deenergized and the contact 76 opened. This reinserts the resistor in the motor circuit and tends to'decelerate the motor. Substantially simultaneously, the segment 57 of the drurr switch 25 bridges its

contacts

51 and 52 completing an obvious energizing circuitfor the coil 770 of the contactor 77. The closing of the contactor 77 the main contactor.

voltage will be applied to themotor for maintaining it in operation at a low speed. The exact speed depends upon the values of the

resistors

75 and 78.

The decelerating portion of the cycle isindicated in Figure 3 by the angleDB and the creeping speed portion by the angle CS. 1

When the motor has operated at creeping speed for a short time, the segment 44 of the drum switch leaves its

contact fingers

42 and 43, breaking the sealing circuit of the coil 720 of The contactor opens immediately to cut ofi the motor from the supply source and deenergize the brake coil 24s. The brake 24 immediately becomes effective and brings the motor to rest within a small portion of the operating cycle indicated by the angle B in Figure 3. Since the motor is always operating at a certain definite low speed when the brake is applied, it will drift a substantially constant amount, for any given adjustment of the brake, so that it will reach substantially the same initial position at the end of every cycle. This drifting movement is sufiicient to cause the segment 57 to move away from its

fingers

51 and 52 to de-energize the contactor 001 77c and open the contact 77 thereof, and to cause segment 44 again to bridge its

contacts

42 and 43. The brake coil 24s is designed so that it will hold the brake in the ofi position as long as the main contactor 72 is closed to maintain the motor in operation at creeping speed.

The shear, its motor, and the drum switch 25 have now been returned to rest at their initial positions and, even though the contacts 20 are bridged by the flag 18, as long as the piece 19 engages the flag, no further operation of the sheet will result until the leading end engages a flag 79. This flag, when engaged by the piece 19, is effective to close momentarily a pendulum switch 80 which is released for return to the off position after the finger of the flag which engages the pendulum slips past the latter. The flag 79 is spaced at a distance from the shear equal to the length of material it is desired to shear for delivery to the cooling bed. .Theso cooling bed lengths are generally longer than the pieces which result from continuous operation of the shear. The pendulum switch 80 is connected in parallel with the push button switch 73 and therefore efiects a complete cycle conforming exactly to that just described as a result or" the operation of the push button switch. After the completion of the cycle and the restoration of normal conditions, a second cooling bed length will be cut, and so on until the piece'has been entirely sheared into cooling bed lengths. When the trailing end ofthe piece leaves the flag 18, the subsequent engagement of the leading end of the last piece shorter than the cooling bed lengths, with the flag 79, will not cause a shearing cycle. In other words, there must be enough material approaching the shear to hold shorter lengths, depending upon the time necessary to eifect a complete cycle, and the speed of travel of the material. One or'both of these variables may be subject to adjustment. The motor 21, for example, may have a shunt winding by which its maximum speed may be controlled. The value of' the resistor '75, furthermore, may be changed to provide different accelerating characteristics. In either case, suc-' cessive operating cycles will be effected by the shear as long as the switch '74 is closed and the flag l8 raised. a

The short lengths cut by continuous operation of the shear are normally not long enoughto operate the flag 79 but the latter would have no eflect even if operated, since it is in parallel with the switch '74, already closed. After the passage of the trailing end of the piece beyond the flag 18, the continuous operation of the shear is terminated until another piece of material approaching the shear raises the flag.

It will be apparent from the foregoing description thatthe system is capable of effecting a single shear out under manual control with automatic shearing of cooling bed lengths, if desired, as well as the continuous shearing of shorter lengths. The invention thus makes it possible to take advantage of the high speed of opera-.

tion characterizing rotary shears, with the ease and flexibility of control necessary to a practical solution of the problem of shearingmaterial into various lengths.

Although I have illustrated and described herein but a single preferred embodiment of the invention, it will be recognized that numerous changes in the apparatus as disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. The combination with a shear adapted to cut moving material in successive cycles, of an electric motor for operating said shear, a mechanical brake for stopping said shear, and conoperable in timed relation to the operation of the motor.

4. The combination with a rotary shear, an electric motor for driving the shear and an electromagnetic brake for stopping the shear, of a switch for starting the motor and a control switch driven by said motor for continuing normal operation thereof for a predetermined period, and subsequently decelerating the motor by dynamic braking, driving it at at reduced speed and finally applying said electromagnetic brake.

5. In a motor-driven shear, a brake for stopping-the shear and control means actuated by the motor for continuing normal operation there of for a predetermined period after an initial start, and for decelerating the motor by dynamic braking, operating it at reduced speed and applying said brake.

6. A motor-driven shear including a brake, means for continuing the operation of the motor after an initial start. and for subsequently decelerating the motor, operating it at reduced speed, and applying said brake.

'7. Control mechanism for a motor-driven rotary shear comprising means for starting and accelerating the shear motor 'to cutting speed, means for decelerating the motor, means for operating the motor at reduced speed, and braking means operative to stop the shear in a predetermined position.

8. In a control system for a motor driven rotary shear, means for accelerating the motor to cutting speed, means for decelerating the motor by applying dynamic braking thereto, and means for mechanically braking the motor to stop the shear in a predetermined position.

9. A control system for a motor driven rotary. shear for cutting lengths of material comprising manually operable means and means operated by r the material to be sheared, effective for accelerating the shear motor to cutting speed, and

means actuated by rotation of the motor for subsequently stopping the motor by successively applying thereto dynamic and mechanical braking.

10. Ashear-motor control system including shear accelerating means, and means actuated by operation of the motor for stopping the motor to stop it at a predetermined position.

trol mechanism including a starting switch, ef-v fective during a shearing cycle to cause starting of the shear, dynamic braking to check the motor speed, and thereafter a mechanical braking operation to stop the motor and shear.

2. Control mechanism for shears including an electric motor, means for driving the motor at creeping speed, a mechanical brake, and means for starting the motor to operate the shears and for eifecting a dynamic braking operation, and I an operation of said creeping speed means and mechanical brake. v

3. Control mechanism for shears including a motor, means for imparting a creeping speed to said motor, a brake',-and means for successively starting the motor to operate the shears, effecting a dynamic braking operation, a creeping speed operation of the motor, and an applica tion ofthe brake, said means including a switch by dynamically braking it, operating it at reduced speed and finally applying a mechanical brake 11. In'a shear-motor control system, means for starting the motor to effect a shearing operation, and means actuated thereby for decelerating the motor, operating it at slow speed and stopping it in a predetermined position.

- i 13 12. In a shear motor control system, a starting switch and a sequence switch driven by the motor for decelerating and deenergizing the motor after starting, a dynamic braking circuit, a creeping speed circuit and a mechanical brake controlled successively by said sequence switch for stopping the motor in a predetermined posiion.

13. The combination with a shear adapted to cut moving material, of a motor for operating the cut moving material, of a motor for operating the shear, a brake, and a sequence switch eifective for producing dynamic braking of the motor, operation of the motor at creeping speed, and

then a setting of the brake.

15. In an apparatus for cutting moving-mate- 5 rial, the combination with a rotary shear,a motor for driving the shear, and means for starting the motor from rest and accelerating it so that the blade of the shear attains a peripheral speed substantially equal to the linear speed of the moving material, of means efiective after a cutting operation for decelerating the motor and stopping the shear at a predetermined initial position.

1,6. In an apparatus for cutting moving material, the combination with a rotary shear, .a motor for driving the shear, and means for starting the motor from rest and accelerating it so that the blade of the shear attains substantially the peripheral velocity of the moving material, of

means driven by the'motor for decelerating it after a cutting operation, and stopping the shear in a predetermined initial position.

17. In an apparatus for cutting moving material, the combinationwith a rotary shear, a mo-' tor for driving the shear, and means for starting the motorfrom rest and accelerating it so that the blade of the shear attains substantially the peripheral velocity of the moving material, a sequence switch driven by the motor for dew celerat-ing it after a cutting operation, and stopping the shear in a predetermined initial position.

o LORENZ IVERSEN.